1. Field
The following description relates to a multiple input multiple output communication (MIMO) system and feeding back channel information in the MIMO communication system.
2. Description of Related Art
Researches have been conducted to provide services, such as multimedia service, at a high quality and high speed. As part of that research, a technology relating to a MIMO communication system that uses a plurality of channels has been rapidly developed.
In the MIMO communication system, a base station may use a spatial division multiplexing (SDM) scheme and a spatial division multiplexing access (SDMA) scheme. That is, the base station may simultaneously transmit a plurality of data streams via a plurality of antennas according to the SDM scheme, and may transmit the plurality of data streams to multiple users via the plurality of antennas according to the SDMA scheme.
To effectively transmit the plurality of data streams via the plurality of antennas, the base station may need to recognize channel information of downlink channels between the plurality of antennas of the base station and at least one user. Accordingly, the at least one user may need to feed back the channel information of the downlink channels to the base station.
The at least one user may need an uplink radio resource to feed back the channel information to the base station. However, providing uplink radio resource may decrease the efficiency of the MIMO communication system and/or increase the overhead of the MIMO communication system.